This invention relates generally to the art of gas cylinders, or tanks, and more specifically to methods and devices for disposing of, or recycling, gas cylinders.
Disposal of hazardous waste is currently regulated in the U.S. by the Resource Conservation And Recovery Act (RCRA) of 1976. Many other developed countries have similar legislation. These laws attempt to control hazardous waste from "Cradle to Grave." One of the items classified as "hazardous-waste" under the RCRA is "contained gas." Thus, gas tanks, or cylinders, which have been used to store, propane, mapp, or oxygen gases, for example, are classified as hazardous waste and they retain this classification until it can be clearly shown that they no longer contain hazardous waste. For this reason, waste handlers charge large fees for disposing of substantially exhausted small propane tanks, for example. In this regard, many companies which regularly use propane gas pay as much as $35.00 per exhausted tank simply to dispose of them. It should be noted that although old gas tanks cannot normally be reused, the material from which they are made, often steel, can be recycled. Notwithstanding this, because they still may contain hazardous waste, waste handlers charge large fees for their disposal.
If users of propane tanks, and waste handlers, could readily, and visually, ascertain that exhausted tanks no longer contain gas, and that it is not possible that they could hold gas, the tanks could be easily and economically disposed of and recycled as scrap steel.
Thus, it is an object of this invention to provide a gas tank evacuator for not only safely evaluating contents of gas tanks, that is for draining residue gases from them, but also for preparing the gas tanks so that it can be clearly and visibly ascertained that they cannot possibly contain hazardous gases.
It is also an object of this invention to provide such a gas tank evacuator which can be employed by users of gas tanks, such as companies which employ large numbers of propane tanks, rather than only by waste handlers.
It is also an object of this invention to provide a gas tank evacuator which is highly portable, but which can be used either as a table-mounted unit or as a hand-held unit.
Yet another object of this invention is to provide a gas tank evacuator which takes very little strength or dexterity to operate and which is uncomplicated and relatively inexpensive in structure.
It is a further object of this invention to provide a method of preparing gas tanks for their disposal which is inexpensive but yet effectively communicates to others a disarmed nature of such thusly prepared gas tanks.
It has been proposed by Michael C. Campbell, in U.S. Pat. No. 5,421,380, issued Jun. 6, 1995 to provide a gas tank evacuator having an evacuator housing into which an attachment neck of a gas tank can be screwed and an elongated valve-removal rod for passing through the evacuator housing to engage a valve of the gas tank at a valve-engaging lower end thereof. The valve-removal rod can be moved longitudinally in the evacuator housing by means of a valve-removal-rod lever which is pivotally attached to the housing and to the valve-removal rod by parallel pivot links. However, a connection between the valve-removal-rod lever and the valve-removal rod also allows the valve-removal rod to rotate in the housing. The gas tank evacuator also includes an elongated valve actuator pin passing through and being slidable in the valve-removal rod for independently actuating the valve of the gas tank.
Thus, the attachment neck of a gas tank can be screwed to the housing with the valve-removal rod pulled longitudinally away from a valve in the attachment neck. The valve-actuator pin can then be moved longitudinally through the valve-removal rod for depressing a stem of the valve of the gas tank to release gas from the gas tank and check gas pressure in the gas tank. Thereafter, the valve-removal-rod lever can be pivoted to drive a valve engaging device at the lower end of the valve-removal rod into engagement with the stem-actuated valve. The valve-removal rod can then be rotated to unscrew the valve from the gas tank, and the valve-removal-rod lever can be pivoted upwardly for removing the valve.
The gas tank evacuator channels gases evacuated from gas tanks through a filter canister which is removably attached to the evacuator housing.
Although this prior art device described by Michael C. Campbell has tremendous benefits over the prior art, it has proven to have some drawbacks. One drawback is that it is rather difficult, and somewhat expensive, to construct the valve-removal rods and the elongated valve actuator pin. In this regard, a bore must be made in the valve-removal rod for rather snugly accommodating the actuator pin and the actuator pin must be specially made. The construction steps for making these elements requires a great deal of machining, which increases expenses. Also, the connection between the valve-removal rod lever and the valve-removal rod is somewhat complicated and expensive to fabricate.
Yet another difficulty with the prior art system of Michael C. Campbell is that after it has been used to unscrew the valve from the gas tank, it is not as easy to see that the gas tank has been disarmed as one would like. That is, one must look down a rather deep hole in the neck of the gas tank in order to verify that the main valve thereof has been removed.
In view of these two shortcomings of the prior art Campbell system, it is an object of this invention to provide a gas tank evacuator which is easier and less expensive to manufacture than is the prior Campbell gas-tank evacuator system, and which, once it has been used to remove a valve from a gas tank, makes it easier to ascertain that the gas tank has been disarmed (that is, that a valve thereof has been removed).